AB0165 BIOMARKERS ASSOCIATED WITH GIANT CELL ARTERITIS IN PATIENTS WITH POLYMYALGIA RHEUMATICA FEATURES
Authors: A. Ramon, H. Greigert, C. Cladière, M. Ciudad, P. Ornetti, J. F. Maillefert, B. Bonnotte, M. Samson
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Polymyalgia Rheumatica (PMR) is a frequent inflammatory rheumatism associated with giant cell arteritis (GCA) in 16-21% of cases. GCA is characterised by large vessel vasculitis which is absent in isolated PMR [1]. The identification of serum biomarkers reflecting vascular involvement could allow the selection of PMR patients in whom further investigations are indicated to confirm or rule out GCA. <h3>Objectives</h3> This study aimed to identify serum biomarkers associated with GCA in a population of patients with PMR features. <h3>Methods</h3> Patients were prospectively enrolled in Dijon University Hospital, France. At inclusion, no patient had yet received glucocorticoids or immunosuppressive treatment. All PMR patients fulfilled 2012 ACR/EULAR classification criteria [2] and GCA was ruled out by at least an exam evaluating temporal arteries (biopsy and/or color doppler ultrasound) and another evaluating large vessels (angio-CT or FDG-PET/CT). All GCA patients fulfilled the 2022 ACR/EULAR classification criteria [3]. Usual clinical, biological, and therapeutic data were recorded at diagnosis. Several serum biomarkers were measured by Luminex assays: CD141, CD146, CD31, ICAM-1, VCAM-1, ANGPTL-4, ANGPTL-6, and C3L1. Student t test or Mann-Whitney test were performed to compare data, as appropriate. The significance threshold was set at P&lt;0.05 (two-tailed). Analyses were performed with Graphpad PRISM software. <h3>Results</h3> Fifty patients with PMR without GCA (isolated PMR) and 33 patients with PMR and GCA overlap were included. In PMR/GCA overlap patients, 14 (42.4%) had aortitis. Serum level of CD141 was significantly higher in the PMR/GCA overlap group in comparison to isolated PMR group (mean = 6854 pg/mL <i>vs.</i> 5558 pg/mL, p = 0.003). The area under cover (AUC) was 0.68 (CI95%: 0.56; 0.80). No differences were found regarding serum levels of ANGPTL-4 (p = 0.39), ANGPTL-6 (p = 0.22), CD31 (p = 0.74), CD146 (p = 0.35), C3L1 (p = 0.75), ICAM-1 (p = 0.94) and VCAM-1 (p = 0.52) between PMR without GCA and PMR/GCA overlap. Likewise, no significant differences were found for the usual markers of inflammation between both groups: ESR (p = 0.22), CRP (p = 0.39) or fibrinogen (p = 0.92). Comparison between PMR without GCA and PMR/GCA overlap with aortitis found higher level of ANGPTL-4 and ANGPTL-6 in isolated PMR patients (median = 160.7 ng/mL <i>vs.</i> 128.9 ng/mL [p = 0.04] and 4.3 ng/mL <i>vs.</i> 3.1 ng/mL [p = 0.02], respectively). CD141 was positively correlated with CD146 (r =0.48; p &lt; 0.001) and VCAM-1 (r = 0.34; p = 0.001). VCAM-1 was positively correlated with CD141 (r = 0.34; p = 0.001), C3L1 (r = 0.35; p = 0.001) and ANGPTL-4 (r = 0.47; p &lt; 0.001) <h3>Conclusion</h3> This study found lower serum concentrations of CD141 in PMR patients without GCA <i>versus</i> those having PMR and GCA overlap. However, the diagnostic performance of CD141 does not appear to be sufficiently discriminative to rule out GCA in PMR patients. ANGPTL-4 and ANGPTL-6 could be interesting serum biomarkers to detect aortitis in patients with PMR features. The study of other biomarkers reflecting endothelial aggression during GCA is needed with larger patients' cohorts. <h3>References</h3> [1]Buttgereit F, Dejaco C, Matteson EL, Dasgupta B. Polymyalgia Rheumatica and Giant Cell Arteritis: A Systematic Review. JAMA 2016;315:2442–58. [2]Dasgupta B, Cimmino MA, Maradit-Kremers H, Schmidt WA, Schirmer M, Salvarani C, et al. 2012 provisional classification criteria for polymyalgia rheumatica: a European League Against Rheumatism/American College of Rheumatology collaborative initiative. Ann. Rheum. Dis. 2012;71:484–92. [3]Ponte C, Grayson PC, Robson JC, Suppiah R, Gribbons KB, Judge A, et al. 2022 American College of Rheumatology/EULAR classification criteria for giant cell arteritis. Ann Rheum Dis 2022;81:1647–53. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.